Chair backrest



FIG. 1 is a front perspective view of chair backrest showing my new design.

FIG. 2 is a front view thereof.

FIG. 3 is a rear view thereof.

FIG. 4 is a left view thereof.

FIG. 5 is a right view thereof.

FIG. 6 is a top view thereof.

FIG. 7 is a bottom view thereof.

FIG. 8 is a perspective view of the chair backrest showing my new design connected to a support unit, wherein the broken lines in the drawing is for illustrative purpose only and shows the portion that forms no part of the design to be claimed; and,

FIG. 9 is a rear perspective view thereof. 

CLAIM The ornamental design for a chair backrest, as shown and described. 